Apparatus for making in the cold screw blanks, rivets, and similar headed articles



Nov. 17, 1925. 1,561,863

- v v J. KUHNE v APPARATUS FOR mmme IN THE cow scnnw BLANKS, a1vms,mm

SIMILAR BEADED ARTICLES Filed Jan. 28, 1924 Fig.1

[22V917i012'f live/4. MAP-Le I 5y I and Similar Headed Articles, for which I,

'3, 1922 Ser. Nr. K.

Patented Nov. 17, 1925.

JOSEPH QII' IBEBLOHF, GER-KANT.

APPARATUS FOR MAKING: IN

THE SCREW BLANKS, BIVITS, AND SIMILAR BEADED ARTICLES.

Application fled January 28, 1924. lerial Io 688,201.

To all whom it may conaem:

Be it known that I, J osnrn Kenna, manufacturer, a citizen of the German Republic,

and residing at Iserlohn; Province of Westpha'lia, Germany, have invented certain new.

and useful Improvements in Apparatus for Making in the Cold Screw Blanks, Rivets,

have filed applicationsin Germany on'July 82600 I 49 19, 1922, Ser. Nr. K. 83046 I/49g; and cember 18, 1922, Ser. Nr. K. 84325 I/49g,

and of which the following is a specifica-' head. In this sleeve is guided a second tion.

The subject-matter of the invention is. a;

modification of the'apparatus for making 'in' the cold screw-blanks, rivets and similar headed articles described and claimed in my co-pending application Serial Nr. 689,- 200, filed January" 28, 1924.

One object of my'pres'ent invention is to prevent the formation of the sharp ed 0:1

urr at the front face of the bolt which, in the process accordin to the aforesaid application, may result mm the mass of the stock flowing into the unavoidable intervening space between the reliminary pressure punc and the hollow p unger surrounding said punch and the stock-end to be upset. Another object is to di use with the ackward movement of sai plunger with res ect to the preliminary stamping unehw ich movement, in the ap aratus escribed in my eo-pending a p cation, must be effected y the pressure 0 material when spread out in the head-form in matrix. a w

ith these objects in view my invention consistsof a nemarrangement andcombination of parts constituting an apparatus for makin screw-blanks, rivets and ar head articles. Reference is made to the annexed drawing in which Figs. 1 to 4 are four sectional side elea larger scale, of the matrix and. the front Q end of the plunger surrounding the prelimi- ;Au st,

1 movement which engages in a groove in the sleeve 9.

the upset nary stamping punch in-the end position of the pressure a pliance, and- Figs. 6 an 7 are siderand front views, respectively, of a hexagon screw-head produced according to the'present invention.

Referrin now to the drawings: a is a stationary die having a matrix a of the size and shape of the head to be formed. This matrix is so sunk into the die a that the final stamping die must enter the matrix in order com etely to close the matrix. b indicates the head of the reciprocating press-slide a, and f a sleeve exchangeably mounted in the sleeve g which is controlled by a spring h tending to 892888 it outwardly, its outward 'ng arrested b y-the screw (1 The latter, in contradistinction to the device shown in m co-pending application Ser. N r. 689,200, oes not constitute part of the stamping die but serves to limit the thrust-of a third sleeve or hollow plunger directly surrounding the pressure pin and serves simultaneous y for laterally closing .the matrix during the first portion of the In the sleeve 9 1S pressing o ration. guided the. ollow plunger g which together with the pressure pin is constitutes the final stam in die proper, and which is axially slida le 1n the sleeve g within certain limits. The plunger q is controlled-by a compression spring 1' which bears against its rear flange g and against a shoulder on the sleeve 9, said ring tending to force the plunger g into the eeve g. A screw engaging in a groove in theplunger g hm1ts this movement in such manner that m the normal position the pressure face of the plunger g is flush with the front face of the sleeve 9. The pl r gas a bone 1' of the diameter of the it? to bore is guided the pressure pm I: which at its rear end bears a 'nst the larger thrust rod m, the large enfi n of the latter hearing a inst the adjustable key 0 of'the slide 0. I which, after a certain vdisplacement ofsaid thrust rod 1 and pressure pin k in the lunlger g, strikes against the rear end 0 the The total length of the pressure pin k e thrust .rod m has a shoulder m? headed. In this I and that portion of the thrust rod 1 which min distance from the is in front of the shoulder m is so related to the length of the plunger 9 that at the end of that movement of the preliminary stamping punch formed by pin is and rod 'm which is independent of the plunger I i. e. when the rod m by means of its SllOlllQBI m positively engages the plunger g, the front end of the pressure pin k willproject a cerlunger Q.

The operation of the escribed apparatus is as follows:

After the rod p to be headed has been fed through the die a the distance corresponding to the mass of material to be shaped, the press-slide 0 is moved leftwardly matrix a the sleeve g and with it the plunger are restrained from further movement wh le the slide 0 and with it the rod 'mand pressure pin 7:: advance with simultaneous compression of the spring it. During that time, the rod-portion projecting from the die a and penetrating the bore i in the plunger 9 is pressed by the pressure pin is into the die space or matrix a}, the mass being spread out laterally all round in said space (Fig. 3). As soon. as the mass is pressed into the matrix the thrust rod m y means of its shoulder m now located at-the rear end of the plun er q, drives the latter forward While simultaneously compressing the spring 1'. In that way the plunger 9 and pressure pin 70, which both now act in common as a final stamping die and enter the die a as such, completely g spreadand press out the mass in the matrix,

that is, convert it to its final form. The

slide a thereupon again moves rightwardly,

the plunger g and sleeve 9 returning to their initial positlonsby the action of springs r and h respectively (Fig. 1). Simultaneously means not shown in the drawing again advance the rod p ,and cut ofif the finished article, whereupon the described operation is re eated.

W en pressing that portion of the rod 7) which is surrounded bythe plunger q into the matrix a the pressure pin lg, at its front and. projects somewhat from 'the plunger q (Figs. 3, 4 and 5) audit keeps this position with respect to the plungerq also when the final pressing occurs. In that way, as Figs. 6 and 7 particularly show, a

small recess or deepening a: is pressed into the front face of the bolt head, the bottom being slipped over the rod portionv of which recess corresponds to the cross section of the pressure pin. The extension of the face of the workpiece associated with that action completely eliminates the sharp, edge or burr which would have formed at the end of the rod 29 adjacent to the pressure pin is when the mass of this rod-end is pressed into the matrix, such formation being due to the mass flowing into the unavoidable intervening space between the pressure pin is and the wall of the bore of the plunger q. The otherwise necessary extra work in removing the small annular burr from the front face of the bolt-head is thus dispensed with.

It is obvious that many changes in the apparatus described may be made without departing from the spirit of the invention. For example, it is not necessary that the pressure face of the plunger 9 in its withdrawn position should be flush with the front face of the sleeve g. On the contrary the device might be modified in such manner that the pressure face of the plunger q lies behind the front end of the sleeve g, whereby still greater room for lateral flow of the mass upset by the pressure pin' is provided between the bottom of the matrix a and the plunger 9. In this case also an alternative is possible in which the plunger 9 at the final pressing does not enter the die a.

The new machine may also be modified in thisway, namely, the rod to be headed, instead of being fed through the die a, may be conducted through an opening laterally of the latter. In this case the blank is cut oil in a manner known per se before being worked up by the pressure devices. The blanks cut off are then introduced between die a and plunger 9 by means of a carrier of a form known per se, the plunger being advanced on to the blank, whereupon the pressing operations proceed in the manner ously on the front of the head either a slit for the insertion of a screw driver or-a multiple sided hole for the insertion of a key. In the first instance the pressure pin is has on its pressure face a projecting rib for forming the slit in the screw-head, while in the second instance the pressure pin is and the bore of the plunger 9 surrounding it have a olygonal cross section, the pres surepin l projecting from the plunger a lUJ against said press-slide, resilient means for coupling said punch and said plunger in the direction oftheir forward stroke, means for temporarily arresting said plunger in such a position that the distance between the bottom of said heacLforming matrix and the front face of said plunger is greater than the finishechheight ofthc head to be formed, and means for positively coupling said punch and said plunger, said lungez', after being positively cou led to saic punch forming together with tie latter a final stamping die.

2. In an apparatus for making in the cold screw-blanks, rivets and similar headed articles, in combination: a press-slide, a sleeve guided therein, a hollow plunger for inclosing the end of the stock to be upset, said plunger being uided for limited longitudinal movement 1n said sleeve, a spring tending to hold said plunger in its innermost position with respect to said sleeve, a stationary die comprisin a head-forming matrix and forming at the same time an abutment for arresting said sleeve, apreliminary stamping punch for pressing said stock-end out of said plunger into said matrix, said punch being guided in the bore of said plunger, a spring for resiliently coupling said sleeve and by the intermediate of the latter said plunger to said punch in the direction of their forward movement, and a shoulder on said punch for positively coupling said punch and said plunger, said plunger, after being positively coupled to said punch forming together with the latter a final stamping die.

3. In an apparatus for making in the cold screw-blanks, rivets and similar headed articles. in combination: a stationary die comprising a head-forming matrlx, apress-shde, a hollow plunger for lnclosmg the end of the stock to be upset, said plunger being slidahly mounted in said'press-sli e, a preliminary stamping punch for pressing said stock-end out of said plunger into said headforming matrix, said punch being guided in the bore of said plunger and resting against said press-slide, means for temporarily arresting said plunger, resilient means for coupling said unch and said plunger in the direction oi their forward stroke, anda shoulder on said punch adapted to abut against the rear end of said plunger for positivelv coupling said punch. and said plunger, the length of that portion of said unch which lies in front 'of said shoulder icing somewhat greater than the length of said plunger, so that the front end of said punch projects from the plunger when the coupling between punch and plunger takes place, said dplunger, after being coupled with the sai punch forming together with the latter a final stamping die.

In testimony whereof I affix my signature.

JOSEPH KUHNE. 

